Another Makefile simplification

Object files for executables (as opposed to modules) will now use the .ro
extension; their dependency file is a .rd file. Currently, this affects only
the i2c/eeprom/eeprom program. but in the future, there will be more
executables generated.


git-svn-id: http://lm-sensors.org/svn/lm-sensors/trunk@52 7894878c-1315-0410-8ee3-d5d059ff63e0

Makefile

@@ -7,7 +7,7 @@
 #  (at your option) any later version.
 #
 #  This program is distributed in the hope that it will be useful,
-#  but WITHOUT ANY WARRANTY; without even the implied warranty of
+	#  but WITHOUT ANY WARRANTY; without even the implied warranty of
 #  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 #  GNU General Public License for more details.
 #
@@ -137,7 +137,7 @@ clean::
 %.d: %.c
 	$(CC) -M -MG $(CFLAGS) $< | \
        	sed -e 's@^\(.*\)\.o:@$*.d $*.o Makefile '`dirname $*.d`/Module.mk':@' > $@
-	
+
 
 # This is tricky, but it works like a charm. It needs lots of utilities
 # though: cut, find, gzip, ln, tail and tar.
@@ -159,3 +159,15 @@ version:
 	echo '#define LM_DATE "'`date +'%Y%m%d'`\" > version.h
 	echo -n 'Version: '; \
 	echo '#define LM_VERSION "'`read VER; echo $$VER`\" >> version.h
+
+# .ro files are used for programs (as opposed to modules)
+%.ro: %.c
+	$(CC) $(EXCFLAGS) -c $< -o $@
+
+%: %.ro
+	$(CC) $(EXLDFLAGS) -o $@ $^
+
+%.rd: %.c
+	$(CC) -M -MG $(CFLAGS) $< | \
+       	sed -e 's@^\(.*\)\.o:@$*.rd $*.ro Makefile '`dirname $*.rd`/Module.mk':@' > $@
+

doc/makefiles

@@ -50,5 +50,16 @@ ones for developers:
     Set to 1 to enable any debugging code. Note that debugging code should
     only output more information, and never make the code mis-behave.
 
+Several files are generated by Makefiles:
+  * .d
+    Dependency files for modules. Automatically generated.
+  * .rd
+    Dependency files for executables. Automatically generated.
+  * .ro
+    Object files for executables. They will be linked together to create
+    the executable. This extension is used to distinguish them from 
+    modules (which end on .o). Also, using a different extensions makes
+    the Makefile fragments much simpler.
+
 There are lots of comments within the main Makefile. Please read them if
 you want to know more.

i2c/eeprom/Module.mk

@@ -25,8 +25,9 @@ MODULE_DIR := i2c/eeprom
 I2CEEPROMTARGETS := $(MODULE_DIR)/eeprom
 I2CEEPROMSOURCES := $(MODULE_DIR)/eeprom.c
 
-# Include all dependency files
-INCLUDEFILES += $(I2CEEPROMSOURCES:.c=.d)
+# Include all dependency files. We use '.rd' to indicate this will create
+# executables.
+INCLUDEFILES += $(I2CEEPROMSOURCES:.c=.rd)
 
 all-i2c-eeprom: $(I2CEEPROMTARGETS)
 all :: all-i2c-eeprom
@@ -37,19 +38,3 @@ clean-i2c-eeprom:
 	$(RM) $(I2CEEPROMSOURCES:.c=.d) $(I2CEEPROMSOURCES:.c=.o) \
 	      $(I2CEEPROMTARGETS)
 clean :: clean-i2c-eeprom
-
-# The targets
-$(MODULE_DIR)/eeprom: $(MODULE_DIR)/eeprom.o
-
-
-# Oops, we need to use EXCFLAGS instead of CFLAGS... And we have to deal with
-# an executable. Ugly code approaching... :-)
-
-$(I2CEEPROMSOURCES:.c=.o):
-	$(CC) $(EXCFLAGS) -c $(@:.o=.c) -o $@
-
-$(I2CEEPROMSOURCES:.c=.d):
-	$(CC) -M -MG $(EXCFLAGS) $(@:.d=.c) | \
-	sed -e \
-        's@^\(.*\)\.o:@$@ $(@:.d=.o) Makefile '`dirname $@`/Module.mk':@' > $@
-